By Suresh Dhaniyala, Bayard D. Clarkson Distinguished Professor of Mechanical and Aeronautical Engineering, Clarkson University, and Byron Erath, Associate Professor of Mechanical Engineering, Clarkson University
A fast-spreading variant of the coronavirus that causes COVID-19 has been found in at least 10 states, including Oregon, and people are asking themselves: How do I protect myself now?
We saw what the new variant, known as B.1.1.7, can do by spreading rapidly across southeastern England in December, causing an increase in the number of cases and triggering stricter blocking measures.
It is estimated that the new variant is 50% more easily transmitted than the common variants, although it seems to affect people’s health in the same way. Increased transmissibility is believed to arise from a change in the virus’s spinal protein that may allow the virus to enter cells more easily. These and other studies on the new variant were launched before the peer review to share their findings quickly.
In addition, there is some evidence that patients infected with the new variant B.1.1.7 may have a higher viral load. This means that they can expel more virus-containing particles when breathing, speaking or sneezing.
As teachers who study fluid and aerosol dynamics, we investigate how virus-carrying particles in the air spread. There is still a lot that scientists and doctors do not know about the coronavirus and its mutations, but there are some clear strategies that people can use to protect themselves.
Airborne particles are still the biggest problem
SARS-CoV-2 variants are believed to spread mainly through the air, not on surfaces.
When someone with coronavirus in the respiratory tract coughs, talks, sings or just breathes, infectious respiratory droplets can be expelled into the air. These droplets are tiny, predominantly in the range of 1-100 micrometers. For comparison, a human hair is about 70 micrometers in diameter.
The largest drops fall to the ground quickly, rarely traveling more than 6 feet from the source. The biggest problem for disease transmission is the smallest droplets – those less than 10 micrometers in diameter – that can remain suspended in the air like aerosols for hours at a time.
How effective are the different types of masks? UNSW / Thorax.
With people possibly having more viruses in their bodies and the virus being more infectious, everyone should take extra precautions and care. The use of facial masks and social distance are essential.
Spaces and activities that were previously considered “safe”, such as some indoor work environments, can be at high risk of infection as the variant spreads.
The concentration of aerosol particles is generally higher alongside the individual who emits the particles and decreases with distance from the source. However, indoors, aerosol concentration levels can increase rapidly, similar to the way cigarette smoke accumulates in closed spaces. This is particularly problematic in spaces with poor ventilation.
With the new variant, levels of aerosol concentration that did not previously pose a risk can now lead to infection.
What can you do to stay safe?
1) Pay attention to the type of face mask you wear and how it fits.
Most ready-to-use facial coatings are not 100% effective in preventing the emission of drops. With the new variant spreading more easily and likely to be infectious at lower concentrations, it is important to select coatings with materials that are most effective in preventing droplet propagation.
When available, the N95 and surgical masks consistently perform best. Otherwise, facial covers that use multiple layers of material are preferable. Ideally, the material should be a fair weave. High thread count cotton sheets are an example. Proper adjustment is also crucial, as gaps around the nose and mouth can decrease effectiveness by 50%.
2) Follow the social detachment guidelines.
While the current guidelines for social distance are not perfect – 6 feet is not always enough – they offer a useful starting point. Because levels of aerosol concentration and infectivity are highest in the space immediately around anyone with the virus, increasing physical distance can help reduce risk. Remember that people are infectious before they start showing symptoms and often never show symptoms, so don’t count on signs of illness.
3) Think well about the environment when entering an enclosed area, both the ventilation and the way people interact.
Limiting the size of meetings helps to reduce the potential for exposure. Controlling indoor environments in other ways can also be a highly effective strategy for reducing risk. This includes increasing ventilation rates to bring fresh air and filtering existing air to dilute aerosol concentrations.
On a personal level, it is useful to pay attention to the types of interactions that are taking place. For example, many screams can create a greater risk than speaking just one. In all cases, it is important to minimize the amount of time spent indoors with other people.
The CDC warned that B.1.1.7 may become the dominant SARS-CoV-2 variant in the US in March. Other fast-spreading variants have also been found in Brazil and South Africa. Increased surveillance and compliance with health guidelines should continue to be the highest priority.